This invention relates to an improved shield incorporated in latch bolt operating devices for shielding the latch driving mechanisms thereof to deter probe manipulation from exterior of and through the exterior face of the door. In the preferred embodiment, the unique shield is retained in the exterior operator assembly of the latch construction longitudinally inwardly against an exterior door face by inward abutment of a guard collar, the guard collar, in turn, being retained by inward abutment of the exterior operator lock cylinder. Thus, the shield is retained in the latch construction assembly in a secure manner for efficiently serving its latch driving mechanism shielding purposes.
It is a well known problem of modern times of attempting to maintain residences and businesses secure from surreptitious entry and burglary. One of the most common forms of attack, of course, is through entry and exit doors. Such doors are attempted to be maintained locked and secured by use of various forms of latch constructions, preferably one or more deadbolt constructions.
The latch constructions used will normally include exterior and interior operators mounted, respectively, at exterior and interior faces of the particular door with the operators being connected interiorly of the door to a latch driving mechanism. The latch driving mechanism is, in turn, operably connected to a bolt arranged for extension and retraction from and to a door edge. The exterior operator includes a lock cylinder exposed outwardly of the exterior door face so that the bolt may be locked in extended position to thereby retain the door in a locked position and against intrusion.
Some years ago it became known to illegal intruders and burglars that these various latch constructions retaining doors locked could be violated by somehow severing the latch construction exterior operators at the exterior door face from the remainder of the latch construction assembly and gaining access to the latch driving mechanism of the latch construction. Once the exterior operator was removed and access to the latch driving mechanism obtained, it was a simple matter to manipulate the latch driving mechanism, withdraw the latch construction bolt and place the door in unlocked condition. Furthermore, it was discovered by police authorities that this severing of the latch construction exterior operators including the lock cylinders thereof was quickly accomplished by use of relatively strong bolt cutters and similar tools.
Thus, in order to attempt to frustrate this means of attack, the manufacturers of latch constructions began improving the exterior operators of latch constructions from the strength standpoint. One of the most efficient and economical means of doing so has been the addition of a relatively thick, hardened metal guard collar to the exterior operator. The guard collar is formed and arranged in the exterior operator assembly securely retained surrounding the vital lock cylinder and also extending longitudinally into the door interior beyond the door exterior face.
As a result, any attempted severing of the exterior operators at the exterior door face by the use of bolt cutters and similar cutting tools required a first penetration of the thick, hardened metal guard collar and would thereby frustrate it. Furthermore, it was found that any attempted penetration by severing tools of the guard collars was made even more difficult by mounting the guard collars rotatable in the assembly in the event of any appreciable forces being applied thereto. This was accomplished by mounting the guard collars in the assembly through mere abutments, although secure abutments, with the associated exterior operator parts.
Since having the exterior operator severing means of attack eliminated, it has been more recently discovered that intruders attempting to violate the latch constructions have resorted to the use of probes inserted through the exterior door faces adjacent the latch construction exterior operators and penetrating at various angular positions to the latch construction latch driving mechanisms. Again, if access to the latch driving mechanisms can be obtained by use of such probe penetration and the person doing so is adept at the correct manipulation, it is possible to manipulate the bolts to withdrawn positions and place the particular door in unlocked condition. It is true that this is a somewhat difficult procedure and manipulation access to the correct portion of the latch driving mechanism must be obtained, it still can be accomplished by those having the necessary knowledge and manipulation skills. It is obvious, therefore, that further protection for the latch driving mechanisms of latch constructions is desirable.